1. Technical Field
The present invention relates to a liquid ejecting head which ejects liquid from nozzle openings and a liquid ejecting apparatus, particularly to an ink jet type recording head which ejects ink as liquid and an ink jet type recording apparatus.
2. Related Art
An ink jet type recording head which is an example of the liquid ejecting head, for example, includes a piezoelectric actuator which is a piezoelectric element on one surface side of a flow path formation substrate on which a pressure generation chamber which communicates with nozzle openings is provided, and ejects ink droplets from nozzles in such a manner that a vibrating plate is deformed due to the driving of the piezoelectric actuator and a change in pressure occurs in the pressure generation chamber.
Herein, there is a proposal of a vibrating plate containing silicon oxide or zirconium oxide on the flow path formation substrate side (for example, see JP-A-2009-83140 and JP-A-2011-88369).
In addition, there is proposed that a protection film having resistance to liquid of a material such as tantalum oxide is provided on an inner wall of a flow path of the pressure generation chamber or the like, for preventing erosion of the flow path formation substrate or the vibrating plate due to the ink in the flow path (for example, see JP-A-2012-143981).
However, although the protection film having resistance to liquid is provided on the inner wall of the flow path, in a configuration in which substrates formed with silicon substrates are laminated to each other, there are problems that the ink invades and erodes adhered boundary surfaces of the laminated substrates, bonding strength decreases due to reduction of adhered boundary surfaces, and malfunctions such as leakage or discharging failure of the ink and peeling-off of the laminated substrate occur.
In addition, although the protection film having resistance to liquid is provided on the inner wall of the flow path, if a pin hole or the like is formed on the protection film, the ink (liquid) in the flow path erodes the silicon substrate through the pin hole.
Further, if the pin hole is formed on the protection film which is provided on the inner wall of the flow path, there are problems that a vibrating property of the vibrating plate is negatively affected due to erosion of the vibrating plate, and there is a difficulty in stably deforming the vibrating plate.
Particularly, in order to realize high density of the nozzle openings and a thin shape of the ink jet type recording head, it is necessary to make the protection film thin, and therefore a problem of the pin hole or the like tends to occur on the protection film.
The problems described above not only occur in the inkjet type recording head, but also occur in a liquid ejecting head which ejects liquid other than the ink.